Info What is Saturation Diving?

[tracydr]

Saturation diving reminds me very much of when I used to do Missile crew on the Minute Man 3 system. Even the meals and ordering the meals is quite similar. We were only down for 24 hours, unless trapped by storms, but going down in that capsule, locking it up and not being able to come out no matter what is very similar. Also, some of the communications equipment and other gear looked familiar.
I really enjoyed the movie. Thanks!

 

[Akimbo]

Forgive me for asking, but is it possible or is there a safety factor in pressurizing a chamber and bringing it to the surface with divers in it with decompression taking place at the surface like a decompression chamber?

I'm not sure I fully understand your question but here goes:

Manned pressure vessels like hyperbaric chambers used in diving and medicine or submersibles (external pressure vessels) are usually required to meet more stringent codes than unmanned vessels. As mentioned by DCBC, the certifying agency in the US is the ASME (American Society of Mechanical Engineers). Pressure vessels fall under two primary divisions. Division 2 is generally much more expensive and less common than Div 1, but produces a lighter weight pressure vessel. Manned pressure vessels must also meet ASME's PVHO (Pressure Vessels for Human Occupancy) standards.

Pressure vessels installed on maritime vessels (boats, ships, and submersibles) in the US must also comply with the Bureau of Shipping's requirements. Similar standards organizations are in Norway, EU countries, and the UK to name a few. Most, if not all, other countries have their own or contract with ASME or others.

Each standard goes far beyond a rule of thumb percentage safety factor. Certs from the producer of the metals and plastics are required. Samples often require destructive testing. Weld shops, engineers, and welders themselves all go through certification tests and inspections. Calculations are specified by the code, performed by the weld shop's certified engineer, and scrutinized by the certifying agency. The welds themselves must be non-destructively tested, and vessels are hydro-tested, and sometimes instrumented.

All this concern goes far beyond the safety of a few divers. ASME came into being in 1880. One of their biggest objectives was to prevent steam boiler explosions. As pressures increased so did the damage around the explosions -- to the point that buildings and ships were destroyed.

 

[iluvtheocean]

2 things -- #1 thank you all for such interesting information that joe public and us rec divers aren't privy to or aware of -- very informative.

i was curious what the living areas of the sat chambers looked like and how many divers are usually in each chamber at a time? and just thought about it - but how does the helium based environment effect how food tastes, what food can be eaten/prepared (and how), and does all of it have effects on waste elimination?
any pictures of what the chambers look like from inside?

 

[Akimbo]

...i was curious what the living areas of the sat chambers looked like and how many divers are usually in each chamber at a time?...

The largest single living chamber I have seen is 8-man, but 4-6 are more typical. The smallest I know of is 3-man. Living chambers and transfer locks are bolted together to support up to about 24 divers.

... and just thought about it - but how does the helium based environment effect how food tastes, what food can be eaten/prepared (and how), ?...

Food is prepared in the galley, often to order. Cooking inside the chamber would outgas too many unknown and difficult to analyze gases and be a fire hazard when shallow. A galley would also take up extremely valuable space and make complex hygiene problems even worse.

The prepared food is transferred into the divers using a utility lock (medical lock in the old days). They consist of horizontal steel tubes welded into the chamber that are anywhere from 10-24" in diameter and 12-40" long. A clamped hatch is on the outside and a simple swinging pressure-seating hatch is inside. Objects are placed inside the lock, a door is closed. Pressure is equalized with the inside or bleed off to the surface depending on which direction the stuff is going. The opposite hatch is opened and stuff is removed. The expensive HeO2 that is bleed off is routed to a reclamation system.

...and does all of it have effects on waste elimination?...

There are several toilet designs. The earliest were just a stainless steel toilet bowl mounted to a hull-penetration with a 1-2" ball valve outside. The diver would manually run water into the bowl and call for a flush when he was done. A very serious accident occurred resulting in a significant part of the diver's large intestines getting sucked out. Fortunately they were only about 300' deep (134 PSI) so the diver could break the seal between him and the seat before all fluids and most soft tissue was sucked out.

Investigating Recreational and Commercial Diving Accidents - Steven M. Barsky, Tom S. Neuman - Google Books

This is not a sea story. I spoke with Mark Banjavich, the president of Taylor Diving & Salvage at the time, and another diver who was onboard -- several years after the accident of course. A medical team was flown out, they were unceremoniously locked in the chamber, and saved the diver's life. Unfortunately his career was over along with having to wear a colostomy bag. A secondary lawsuit was filed because one of the docs had a heart attack; none of them had any idea they were being committed to saturation decompression.

CARTER v. TAYLOR DIVING & SALVAGE COMPANY | Leagle.com

All hyperbaric toilets have been interlocked between a bowl cover and the dump valve ever since. Some are just standard stainless steel toilet bowls and others are actual pressure vessels.

Commercial Diving Equipment -Hyperbaric Chamber Toilet

Shower facilities are basically standard shower heads fed by a regulated hot and cold potable water supply. Most are in the transfer or outer lock which is a wet area. Most of the systems I have seen just let the water run into the chamber bilge and a valve is periodically opened to blow the water out.

EDIT, 22 June 2018: See Taylor Diving & Salvage: Emergency Surgery in Saturation

... any pictures of what the chambers look like from inside?

A lot of these guys here have more recent photos than I do so I will let them post.

 

[DCBC]

...any pictures of what the chambers look like from inside?

[video=youtube;DsnYH0YLTRo]http://www.youtube.com/watch?v=DsnYH0YLTRo[/video]

 

[Akimbo]

Here's an image of the bell and handling system on the deck of the Lewek Toucan, which rescued the cook on the Jackson 4.

http://www.scubaboard.com/forums/ac...8-jascon-4-rescue-video-3-days-30m-lived.html

She is 289'/88 M long and built as an Anchor Handling Vessel... small for purpose-built DSVs by North Sea standards. See what I mean about it being difficult to get an image of bell handing systems that didn't look like a jumble of machinery? At least this one is on the open deck so you can get the camera back far enough.

 

[Akimbo]

Here is a post from a thread referenced above: http://www.scubaboard.com/forums/accidents-incidents/399964-six-divers-trapped-sea-bottom.html. I felt it was worth reposting here because it explains another common question:

What happens if the vessel sinks and you are have days of decompression left?​

A hyperbaric lifeboat is a modern covered lifeboat with a chamber and life support systems inside. To my knowledge none have been used in an emergency... yet.

All things considered, I would prefer to have a hyperbaric lifeboat onboard than not. But I don’t know many divers that put much faith in them.

Consider that most bells are in the water ~22/day. Larger purpose-built diving support vessels have two bells and a 24-man crew in saturation. Two working crews may be at different depths and 4-8 are decompressing out for a crew change. So let’s say you have a crew at 50' with ~16 hours of decompression left. Another working crew at 300' and another at 600'.

Now picture both bells on the bottom with a tender in each and a diver locked out. The ship suffers server damage and lists to 30°. The diving supervisor orders divers back to the bells and starts blowing the two shallow crews down to 600'. He considers blowing them all down about 50' deeper than the bottom in case she sinks and they need to try a rescue from the wreck. At least they wouldn’t drown before hitting the bottom. He hopes like hell he can recover the bells at that list angle in a heavy sea.

Meanwhile, shipping containers, gas tube trailers, and working loads start breaking loose from their lashings and slide around the deck. Hopefully they fall overboard before destroying lifeboats, launch gear, banks of HP oxygen 12-packs, or one of the bells. A pressurized bell or 3000 PSI tube trailer exploding would take out the entire vessel and do serious damage to any platform they may be next to.

Both bells are recovered and mated. The deep crew starts manning the hyperbaric lifeboat waiting for the shallower and bell crews to arrive. The crew from 50' is suffering severe compression pains and bordering on hyperthermia due to heat of compression (Helium is much worse). Everybody is finally in the hyperbaric lifeboat and the hatches are sealed. The diving support crew vents pressure in the transfer trunk, opens the mating clamps, and the lifeboat can be unmated. At this point several diving support crew climb aboard the lifeboat, get launched into the sea, and motor off until they can be recovered by another suitably equipped diving support ship. Of course this is assuming the list doesn't prevent launching. If not, the lifeboat crew will risk their lives and hope they survive the ship sinking under them.

Say there is a rescue ship within 100 miles but she has a smaller system that supports 12 and are in sat at 800’. They also have a crew decompressing in another set of chambers who are at 150'. The rescuing diving super debates whether to blow them down to 800' because they will need the space and scrubber capacity or keep bringing them up. The only option is to press the lifeboat down 200' more and welcome them aboard. The rescue ship will have to launch their hyperbaric lifeboat in order for the rescued boat to mate. It is crowded, environmental control systems are designed for 12 divers, but the lifeboat augments. They all reach the surface about 10 days later unless they can find a second rescue ship to share the load.

I wouldn’t be too critical if a hyperbaric lifeboat wasn’t onboard this vessel. You can Google “Hyperbaric Lifeboat” and see lots of photos and drawings. Perhaps this will help you appreciate my dismissive attitude towards hyperbaric lifeboats. The reality is it would be a miracle if most of the topside crew could be saved. We all wish we could do something when things like this happen. Your thoughts are in the right place.

Anyone considering a saturation diving career should read the entire thread.

 

[DCBC]

Here are a few pictures of a Self-Propelled Hyperbaric Lifeboat for those who may be interested:



IMCA Policy requires an Employer to ensure that the SPHL is capable of a minimum of 24 hours of independent life support and that a plan for recovery of the unit is achievable within that time.

Obviously if the situation dictates that the SPHL be deployed, matters are dire. Diving Superintendents are generally responsible to have a plan in-place that will in-fact deal with the emergency. Matters can change in any crisis, but I've always felt that baring any further tragedy, the safe recovery of the Divers would be assured. What many people don't appreciate is the degree of resources that are brought to bear in the case of emergency.

 

[DCBC]

The photo on the right shows the SPHL's Head. The "Head Tender" seats are those which flank the Head. For anyone who has been in a SPHL (or any enclosed lifeboat) sea-sickness is very common, even for an old salt. Proximity to the Head may initially seem to be advantageous, but as this is the focal point for the discharge of waste, this isn't considered to be the best seat in the house...

 

[Akimbo]

Has anyone mentioned that modesty is not considered a compatible trait in saturation diving?